<div>

    <script 
        src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js">
    </script>

    <script>
        $(document).ready(function() {

	       $('#addFile').click(function() {
		   var fileIndex = $('#upload_file tr').children().length;
		   $('#upload_file').append(
				'<tr><td>'+
				        '<input type="file" name="files['+ fileIndex +']" />'+
				'</td></tr>');
	        });
	
        });
    </script>
    
	<div>
	
	      <table id="upload_file"></table>
	      
	<div>
	   <input id="addFile" type="button" value="Aggiungi File" />
    </div>
	
	</div>
	
</div>
